/*
 * Copyright (C) 2005 Joe Walnes.
 * Copyright (C) 2006, 2007, 2008, 2009, 2011, 2015 XStream Committers.
 * All rights reserved.
 *
 * The software in this package is published under the terms of the BSD
 * style license a copy of which has been included with this distribution in
 * the LICENSE.txt file.
 *
 * Created on 20. March 2005 by Joe Walnes
 */
package com.feilong.lib.xstream.mapper;

import java.util.EnumSet;
import java.util.HashMap;
import java.util.Map;

import com.feilong.lib.xstream.converters.ConverterLookup;
import com.feilong.lib.xstream.converters.SingleValueConverter;
import com.feilong.lib.xstream.converters.enums.EnumSingleValueConverter;
import com.feilong.lib.xstream.core.Caching;

/**
 * Mapper that handles the special case of polymorphic enums in Java 1.5. This renames MyEnum$1 to MyEnum making it less
 * bloaty in the XML and avoiding the need for an alias per enum value to be specified. Additionally every enum is
 * treated automatically as immutable and non-refrenceable type that can be written as attribute.
 *
 * @author Joe Walnes
 * @author J&ouml;rg Schaible
 */
public class EnumMapper extends MapperWrapper implements Caching{

    private transient AttributeMapper                  attributeMapper;

    private transient Map<Class, SingleValueConverter> enumConverterMap;

    /**
     * @deprecated As of 1.3.1, use {@link #EnumMapper(Mapper)}
     */
    @Deprecated
    public EnumMapper(Mapper wrapped, ConverterLookup lookup){
        super(wrapped);
        readResolve();
    }

    public EnumMapper(Mapper wrapped){
        super(wrapped);
        readResolve();
    }

    @Override
    public String serializedClass(Class type){
        if (type == null){
            return super.serializedClass(type);
        }
        if (Enum.class.isAssignableFrom(type) && type.getSuperclass() != Enum.class){
            return super.serializedClass(type.getSuperclass());
        }else if (EnumSet.class.isAssignableFrom(type)){
            return super.serializedClass(EnumSet.class);
        }else{
            return super.serializedClass(type);
        }
    }

    @Override
    public boolean isImmutableValueType(Class type){
        return (Enum.class.isAssignableFrom(type)) || super.isImmutableValueType(type);
    }

    @Override
    public boolean isReferenceable(final Class type){
        if (type != null && Enum.class.isAssignableFrom(type)){
            return false;
        }else{
            return super.isReferenceable(type);
        }
    }

    @Override
    public SingleValueConverter getConverterFromItemType(String fieldName,Class type,Class definedIn){
        SingleValueConverter converter = getLocalConverter(fieldName, type, definedIn);
        return converter == null ? super.getConverterFromItemType(fieldName, type, definedIn) : converter;
    }

    @Override
    public SingleValueConverter getConverterFromAttribute(Class definedIn,String attribute,Class type){
        SingleValueConverter converter = getLocalConverter(attribute, type, definedIn);
        return converter == null ? super.getConverterFromAttribute(definedIn, attribute, type) : converter;
    }

    private SingleValueConverter getLocalConverter(String fieldName,Class type,Class definedIn){
        if (attributeMapper != null && Enum.class.isAssignableFrom(type)
                        && attributeMapper.shouldLookForSingleValueConverter(fieldName, type, definedIn)){
            synchronized (enumConverterMap){
                SingleValueConverter singleValueConverter = enumConverterMap.get(type);
                if (singleValueConverter == null){
                    singleValueConverter = super.getConverterFromItemType(fieldName, type, definedIn);
                    if (singleValueConverter == null){
                        @SuppressWarnings("unchecked")
                        Class<? extends Enum> enumType = type;
                        singleValueConverter = new EnumSingleValueConverter(enumType);
                    }
                    enumConverterMap.put(type, singleValueConverter);
                }
                return singleValueConverter;
            }
        }
        return null;
    }

    @Override
    public void flushCache(){
        if (enumConverterMap.size() > 0){
            synchronized (enumConverterMap){
                enumConverterMap.clear();
            }
        }
    }

    private Object readResolve(){
        this.enumConverterMap = new HashMap<>();
        this.attributeMapper = (AttributeMapper) lookupMapperOfType(AttributeMapper.class);
        return this;
    }
}
